In recent years, wireless communications technologies have greatly developed, and an existing commonly used wireless communications network includes a cellular network. In a cellular network, when a data packet is transmitted between two UEs between which a transmission distance is relatively long, the data packet needs to be transmitted from a transmit end to a base station and then transmitted from the base station to a receive end. In the foregoing transmission process, two air interface resources need to be occupied. When a transmission distance between two UEs is relatively short, in order to save an air interface transmission resource and reduce an overhead of control signaling of a base station, communication may be performed in a device-to-device (Device to Device, D2D for short) manner, that is, communication is directly performed between UEs and forwarding by a base station is not required.
When D2D communication is performed between UEs, two types of signals generally need to be sent: a first type of signal is a scheduling assignment (Scheduling Assignment, SA for short) signal, and a second type of signal is a data (Data) signal. The SA signal is used to indicate a resource used by the data signal and a time adjustment amount obtained when the data signal is received.
Generally, when D2D communication is performed between two UEs, a transmit end first sends an SA signal to a receive end, so as to indicate, to the receive end, a time adjustment amount and a subframe that is used by the transmit end for sending a data signal. The receive end determines, according to the time adjustment amount and the subframe that are indicated in the SA signal, an initial time point of receiving the data signal, where the subframe is used by the transmit end for sending the data signal; and starts to receive, from the determined initial time point, the data signal sent by the transmit end.
However, in this method for transmitting a data signal, if multiple UEs send data signals in a same subframe, interference is easily caused between the data signals sent by the multiple UEs, and as a result, an accuracy rate of receiving a data signal by a receive end is affected.